Protein overexpression leads to growth inhibition and decreased expression of native proteins. This effect is mostly due to competition for RNAP and ribosomes. This competition affects also synthetic biology circuits, which may not behave as expected. The aims of this project are to: (1) characterize/quantify the effect of competition for RNAPs and ribosomes on synthetic genetic circuits; (2) determine the extent to which RNAPs or ribosomes are limiting; (3) develop models that predict the change of behavior of circuits due to competition; (4) demonstrate the predictions on the design of a synthetic cascade. We have constructed a synthetic circuit in E. coli and characterized through theory and experiments the effect of competition on the expression of a constitutively expressed gene when a different inducible gene is activated. For this system, we have also developed predictive models, both analytical and computational. Our finding quantifies the extent of competition and provides initial tools to predict this effect. Our experimental results and models will enable design methods for next-generation circuits that are robust to competition (to be investigated later). This ability will be critical for constructing large circuits reliably.